1. Field of the Invention
The present invention relates to an image processing apparatus and image processing method for performing image processing of a tomographic image acquired by an optical coherence tomography imaging apparatus.
2. Description of the Related Art
In recent years, optical coherence tomography imaging apparatuses utilizing the principle of optical coherence tomography (which will be hereinafter abbreviated as OCT) have been put to practical use. In the optical coherence tomography, measuring light is made incident on a predetermined portion of an object to be inspected, and the structure of the object in the depth direction at the position at which the measuring light is incident is imaged on the basis of interference light of the reflected or diffused measuring light and reference light from a reference object. With this apparatus, light is made incident on the fundus to scan the retina, thereby acquiring a two-dimensional or three-dimensional tomographic image of the fundus. This enables the observation of the fundus.
In order to improve the image quality (specifically, the S/N ratio) of a tomographic image acquired by the OCT, there has been developed a known technique in which a plurality of images are averaged to generate a high-quality tomographic image. Japanese Patent Application Laid-Open No. 2008-237238 discloses a technique of generating a high-quality still image by creating a new tomographic image by computation on the basis of a tomographic image in a cross section adjoining to the cross section of a tomographic image of a retina capture beforehand.
In the prior art described in Patent Application Laid-Open No. 2008-237238, the scanning position with respect to the sub-scanning direction is varied. Therefore, if the eyeball moves in the sub-scanning direction, it is possible that a tomographic image cannot be captured at a desired position and that a high-quality composed image cannot be formed.
Moreover, in this prior art, since consecutive images are selected from among tomographic images captured during scanning to form a still image, the number of images to be composed to form a new image is generally fixed. Therefore, there is a limit to the image quality.